A new study suggests that the dose of the hormone in common contraceptives can be significantly reduced while still being effective in preventing ovulation.
The scientists behind the study believe their findings could provide new insight into the complexities of the endocrine system and support the need for more precise and individualized hormonal contraceptives, a step that could benefit many people.
Mathematician Brenda Lynn A. Javina of the University of the Philippines Diliman and colleagues from the Philippines, Korea, the United States and Denmark built mathematical computer models to explore the optimal timing and dosing of hormonal contraceptives to see if doses — and thus, potential side effects — could be reduced.
It regulates the endocrine system and influences the development of the human menstrual cycle in multiple stages by secreting hormones from the hypothalamus, pituitary gland, and ovaries.
To learn more about the interactions of these hormones, Javina and her team collected information on pituitary and ovarian hormone levels from 23 healthy women between the ages of 20 and 34, all of whom reported regular menstrual cycles that lasted between 25 and 35 days and showed that they had regular menstrual cycles. Evidence of ovulation in the last menstrual period.
The researchers used this real-life data to create a mathematical model of a normal menstrual cycle, enabling them to predict daily levels of hormones during a normal menstrual cycle and to explore the effects of exogenous hormone administration on these levels.
The most common methods of contraception—the pill, injection, and implant—inject one or both of the synthetic hormones, estrogen and progesterone, into your bloodstream to prevent pregnancy.
Synthetic hormonal contraceptives suppress ovulation, prevent the release of eggs and fertilization, and alter cervical mucus to impede sperm and prevent egg implantation.
The modeling was able to make predictions of not only the minimum dose of these hormones needed to achieve contraception but also the effects of the combination of estrogen and progesterone and the optimal timing of dosing.
“Many previous modeling studies have examined the menstrual cycle, how it is formed, and how it can be changed,” the authors wrote in their published paper.
“To the best of our knowledge, our work is the first to use modeling to study the timing of dosing, and thus reduce the dose even further.”
The method used for modeling, known as optimal control theory, is certainly not new. Previous research has used it to show how treatment protocols can be improved in diabetes and prostate cancer and, according to the study authors, to prescribe optimal hormone doses for in vitro fertilization (IVF).
The team now believes the same approach could be used to help improve hormonal contraceptive dosing. However, they note that their model does not account for variance in cycle length, which varies within and between people.
Modeling suggests that birth control pills can work effectively with much lower doses of estrogen or progesterone than are currently prescribed and that taking the hormones at specific times during the menstrual cycle can be more effective than taking them continuously.
“The results show that it is possible to reduce the total dose by 92 percent in estrogen monotherapy, and by 43 percent in progesterone monotherapy,” and that it is more effective to deliver contraceptive estrogens in the mid-follicular phase, the team wrote.
And when both hormones are taken together, they find that even low doses of each hormone can be enough to prevent pregnancy.
“Finally, we showed that by combining estrogen and progesterone, the dose can be lowered further,” the team adds.
Ovulation suppression is useful for more than just birth control; It can help relieve annoying, painful, and sometimes downright painful PMS symptoms and, perhaps surprisingly, reduce the risk of an ACL injury.
Although we’ve used hormonal contraceptives for decades, the full effects are still not well understood.
“Despite the many benefits,” Javina and his team wrote, “adverse side effects associated with higher doses, such as thrombosis and myocardial infarction, cause reluctance to use.”
Of course, it would be ideal if everyone shared the responsibility for contraception equally, and we’re exploring solutions, including other non-hormonal avenues, even though they prove complex.
At the same time, more research is sorely needed to improve existing contraceptives, given their serious side effects.
“The results of this study have the potential to make contraceptive access available to more women,” the researchers say, “in particular because lower doses also reduce the risk of adverse side effects.”
While this work remains a modeling exercise for now, it highlights the benefits of ongoing research to improve commonly used contraceptives.
The peer-reviewed study has been published in PLOS Computational Biology.